12 GeV MOLLER U PDATE TO THE H ALL A C OLLABORATION Juliette M. Mammei

O UTLINE Physics motivation Description of the experiment Update on spectrometer design (since Magnet Advisory Meeting) Status and Future Plans 2 Hall A Summer 2011 Collaboration Meeting

PV M OLLER SCATTERING 3 Hall A Summer 2011 Collaboration Meeting e- Z0Z0 12 GeV MOLLER A PV ≈ 35 ± 0.7 ppb A SEARCH FOR NEW PHYSICS

C OMPLEMENTARY TO THE LHC 4 Hall A Summer 2011 Collaboration Meeting Petriello et. al. (2009) 0.1% measurement of sin 2 θ W !

C OMPARISON TO Q WEAK MOLLER Qweak Target 150 cm, 5kW 35 cm, 2.5 kW Magnet 1550 A/cm A/cm 2 Incident rate 20 GHz/sector 0.8 GHz/sector Asymmetry 35 ± 0.7 ppb 200 ± 5 ppb “Beam properties” ~0.2 ppb ~2 ppb 5 Hall A Summer 2011 Collaboration Meeting

E RROR B UDGET 6 Hall A Summer 2011 Collaboration Meeting o Dedicated measurements with auxiliary detectors Q2, transverse and inelastic asymmetries, pions o Careful design beam properties (1 st and 2 nd order – work at laser table) transverse (take advantage of cancellations) neutrals (design a “2-bounce” collimation system) o Improvements to polarimeters

T HE E XPERIMENT 7 Hall A Summer 2011 Collaboration Meeting two-toroid spectrometer (focus Møller electrons from mrads) detectors located 28 m downstream (~150 GHz rate, <10% bkgd) 150 cm high power liquid hydrogen target 11 GeV, 75 μA beam Picture thanks to Patrick Rogan, UMass undergrad SOLIDWORKS STUDENT EDITION

100% A ZIMUTHAL A CCEPTANCE 8 Hall A Summer 2011 Collaboration Meeting Forward Backward ForwardBackward e- COM Frame e- Lab Frame Identical particle scattering!

TOSCA 9 Hall A Summer 2011 Collaboration Meeting Use GEANT4 with a TOSCA- generated field map Use GEANT4 with a TOSCA- generated field map Commercial software available from Vector Fields for finite element analysis Tracking of particles with no radiative effects Magnetic Forces CAD-like capability Physical layout of coils Support structure Export to step file

C ONDUCTOR L AYOUT 10 Hall A Summer 2011 Collaboration Meeting Biot-Savart calculation optimized current returns Actual conductor layout

T RACKING IN TOSCA 11 Hall A Summer 2011 Collaboration Meeting

GEANT4 R ESULTS (O RIGINAL P ROPOSAL M ODEL ) 12 Hall A Summer 2011 Collaboration Meeting Radius (m) ϕ (degrees) θ lab (degrees) θ cm (degrees)

13 Hall A Summer 2011 Collaboration Meeting GEANT4 R ESULTS (TOSCA M ODEL – ACTUAL C ONDUCTOR L AYOUT ) Radius (m) ϕ (degrees) θ lab (degrees) θ cm (degrees)

14 Hall A Summer 2011 Collaboration Meeting PropertyUpstreamHybridQweak Field Integral (T·m) Total Power (kW) Current per wire (A) Voltage per coil (V) Current Density (A/cm 2 ) Wire cross section (ID: water hole, in) 0.229x0.229 (0.128) 0.229x0.229 (0.128) 2.3x1.5 (0.8) Weight of a coil (lbs) Magnetic Forces (lbs) M AGNET S TATS

B ACKGROUNDS 15 Hall A Summer 2011 Collaboration Meeting Field Map Moller (GHz) Elastic ep (GHz) Inelastic ep (GHz) Background (%) Proposal TOSCA Other sources of background include: scattering from aluminum target windows multiple-bounce photons (minimize 1-bounce) neutrons weak decays with large analyzing power To be studied with GEANT4 simulation!

S TATUS AND F UTURE P LANS Plan to do 3 runs: 14 PAC days – Achieve statistical precision of E PAC days – Focus on systematics, 25% statistical 235 PAC days – All the kinks ironed out FY 2011 MIE proposal to be submitted to DOE DNP by end of June (start of CD process) FY Complete design and engineering FY Construction funding 2016 Assembly in Hall for first run, ~3 months (commissioning + 14 PAC days) 16 Hall A Summer 2011 Collaboration Meeting

E XTRA S LIDES 17 Hall A Summer 2011 Collaboration Meeting

S UPPORT S TRUCTURE 18 Hall A Summer 2011 Collaboration Meeting 3.6 m 7 m

J EFFERSON L AB 19 Hall A Summer 2011 Collaboration Meeting Parity quality beam >85% using strained GaAs photocathodes Upgrade to 12 GeV beam energy, addition of a new Hall “D” 12 GeV MOLLER will run in Hall A with an 11 GeV, 75 μA beam 150 cm high power liquid hydrogen target detectors located 28 m downstream (~150 GHz rate, <10% bkgd) two-toroid spectrometer (focus Møller electrons from mrads) Picture thanks to Patrick Rogan, UMass undergrad SOLIDWORKS STUDENT EDITION

T WEAKING THE OPTICS 20 Hall A Summer 2011 Collaboration Meeting Moller (ee) Mott (ep) Beam (centered at x=0, y=0)

100% A ZIMUTHAL A CCEPTANCE 21 Hall A Summer 2011 Collaboration Meeting Forward Backward ForwardBackward e- COM Frame e- Lab Frame

S PIN P RECESSION AT J EFFERSON L AB 22 Hall A Summer 2011 Collaboration Meeting

E RROR B UDGET 23 Hall A Summer 2011 Collaboration Meeting Simulation, dedicated tracking detectors Careful work at laser table, cancellation with helicity reversal Compton/ Moller polarimeters Average over sectors, forward/backward cancellation Measurements of asymmetry between peaks Dedicated detectors

O UTLINE sin 2 θ W Interference of Z boson with single photon Moller scattering Comparable to 2 highest energy exp. Description of the 12 GeV MOLLER experiment apparatus High rate, small backgrounds – 150 GHz, 8% backgrounds Two toroids Novel toroid design (TOSCA and GEANT4) Angular acceptance mrads 150cm target, detectors at 28m Multiple current returns High power 24 Hall A Summer 2011 Collaboration Meeting